The invention relates to a container lock including an upper and a lower locking lug capable of being passed into a respective lock groove in juxtaposed container corners and turned so as to lock therein in that the lower locking lug is pivotally and translationally mounted in a housing connected to the upper locking lug by means of a shaft capable of limited movement in the axial direction, which shaft is lock-actuated by a spring in the housing in a downward direction, and between the housing and the shaft there are arranged guide means which permit a locking rotation of the lower locking lug on upward movement of the shaft.
DE 195 34 767 A1 makes known a container lock having two mutually rotatable lugs. These lugs are capable of moving vertically relative to one another. When two containers are brought together, the lugs are released. They are under spring tension and pivot into engagement or locking position. This locking position can be released by means of a handle mechanism.
DK 157987 B makes known a container lock having a lower locking lug which is pivotally mounted in a housing connected to the upper locking lug. Spring pre-tensioning is used for the lower locking lug.
According to the invention, there is proposed a container lock as mentioned above, characterised in that the lower locking lug is designed to have a pressure ball intended for abutting interaction with a bottom of a lock groove when an upper container is placed on a lower container, so that the housing is thus pressed down over the shaft, thereby forming a gap between a downward facing circumferential annular surface on the shaft and the lower part of the housing, and in that in the housing there is arranged a locking device, including spring-actuated locking arms which will move in towards the shaft to a position in the gap below the circumferential annular surface and thus as a spacer prevent the return axial movement of the shaft.
A container lock of this kind can by means of its upper locking lug be passed into a lock groove in a subjacent container corner and turned so as to lock therein. A container lock of this kind is arranged in each corner of the container. The container can then be brought into position over another container by means of suitable lifting tackle and lowered down thereon so that the respective lower locking lugs pass into the upward facing lock grooves in the upper container corners of the lower container. The spherical end faces of the lower locking lugs will come to rest against the bottom of the respective upward facing lock grooves. Thus, the lower locking lug and associated shaft will be displaced upwards in the housing, with simultaneous locking rotation as a consequence of the said guiding means between the housing and the shaft.
The two containers will now be locked together and the lower container can thus be lifted together with the upper container.
The unlocking force will be very small, almost zero, because the supporting arms can swing relatively freely out of and into the gap which will be formed between the head of the shaft and a lower face in the housing when the vessel, for example, is in dock, but is almost impossible to open when the vessel heels at speed on the open sea.
Instead of the upper container, there may be used a lifting yoke having four so-called container corners wherein the container locks can be inserted.
It is particularly advantageous if the locking arms of the locking device include a hinged pair of claws designed to have interacting swivel toothing and which grip about the shaft.
Furthermore, it would be advantageous to provide a spring-actuated operating member for the locking arms.
The operating member of the locking device and tension spring may to advantage be arranged in a radially projecting part of the housing.
Advantageously, the spring for tension-actuation of the shaft may also be a spring which acts against the free end of the shaft.
The said guide means can advantageously include a helical guide groove on the shaft and a guide pin fixedly arranged radially in the housing and which runs in the guide groove.
In the upper locking lug or housing there may advantageously be provided ball-and-groove locking pins intended for interaction with walls in a lock groove.
The shaft may to advantage be a screw bolt which is screwed into the lower locking lug.
It is especially advantageous if the housing is sealed off from the outside and filled with oil or the like.
The said operating member can according to the invention advantageously be drive-connected to an electromagnet.